1. Field of the Invention
The present invention relates to a cutting device for a machine having two support rollers which form a winding bed where a roll of finished material, such as a paper web, is wound, one of the support rollers being partially wrapped by a web of material, and the cutting device being advanced upward from underneath the rollers and introduced into a space between the support rollers for cutting the web of material after the roll has been wound.
2.Description of the Prior Art
A winding machine is shown in Federal Republic of Germany 31 09 587 C1 and involves taking measurements between the blade and the outer surface of the roller in order to avoid damage to the drive surface of the web-wrapped roller by the blade during cutting of the web. For this purpose, the blade carrier has associated with it a holding member which can rest on the paper web, and thus on the outer surface of the web-wrapped roller, at the time of cutting, so that a certain minimum distance remains between the cutting edge of the blade and the outer surface of the roller.
Another winding machine is disclosed by Federal Republic of Germany AS 29 30 474. Here, the narrow edge of a holding member 10, which is provided with recesses, cooperates with a perforating blade 21 which includes corresponding tabs. The blade is moved towards the holding member substantially in the circumferential direction of the support roller and remains at a distance from the surface of the support roller. In this manner, separate mountings are provided for the holding member and the perforating blade, and a separate swing drive for each is required.
Reference is made to Federal Republic of Germany OS 29 20 707 where the cutting edge of a blade is pressed against the outer surface of corresponding support roller, as a result of which the roller may be damaged.
Federal Republic of Germany OS 26 38 368 concerns a winding machine in which a cutting device is moved via a pneumatic unit from above, over one of the two support rollers, and against the paper web to be cut, operating in a manner different from the present invention.
The winding machine in accordance with Federal Republic of Germany 41 28 095 A1 which corresponds to U.S. Ser. No. 07/931,244, now U.S. Pat. No. 5,271,573, solves a particular problem which arises when cutting heavy stiff papers. If the finished wound roll is pushed out of the winding bed so that the web to be cut rests under tension against the cutting edge of the blade, a force is thereby exerted on the blade and thus on the blade carrier as well as on the entire web cutting device. The web cutting device consists in general of a machine-wide plate which is supported on both ends. This plate, and possibly the blade carrier, are bent due to the action of the above forces. If the blade is no longer particularly sharp, as a result of bending, the web may not be cut at all.
In accordance with this problem, the blade carrier is arranged as a double lever, one end of which bears the blade while the other end (the support end) forms, during the cutting process, the support for the blade carrier on the outer surface of the web-free support roller, so that a self-locking mounting of the blade carrier takes place.
The disclosures of all prior art materials mentioned herein are expressly incorporated by reference.
Such a machine has been proven excellent in practice. However, once again, the problem arises that the open space within the winding bed, formed between the two support rollers, is limited in its upper region by the outer surface of the paper roll. If the paper roll has a large diameter, it does not extend far enough into the space between the two support rollers. But, on the other hand, if the paper roll has a small diameter it may extend too far downward into the space between the two support rollers. Thus, the height of the space between the two support rollers in the region of the winding bed varies depending upon on whether a paper roll of large diameter or a paper roll of small diameter is resting on the support rollers.
In this machine, when the cutting device is brought into position, it is moved upward a given distance by a suitable means, namely to such an extent that the blade carrier can be tilted into an inclined position, where one blade-bearing end faces the web of goods while the other end, the support end, rests against the outer surface of the support roller that is not wrapped by a web. After the blade carrier has been tilted into the inclined position, the entire cutting device, including the blade carrier, is then lowered a small distance. This means that before cutting the web, the described cutting device must be moved to a somewhat higher position than is necessary to perform the cutting work. In view of the limitation of the space between the two support rollers, as described above, this can be critical in the case of a roll having a small diameter, where the height of the space is not sufficient to initially raise the cutting device to the necessary height.